#defaults=no
#patchname=no
<?

// Delta Thing - Version 2

int DELTA_FROM_RANGE = 1;
int DELTA_FROM_VALUE = 2;

// delta() - returns the changed parameter value
//   v - the parameter's current value
//   vmin - the minimum of the range of v
//   vmax - the maximum of the range of v
//   dt - type of delta, either from a value chosen from the range,
//        or a value which is a percentage of the current value
//   cp - probability of there being a change, from 0.0 to 1.0
//   cb - change bias is from -1.0 to 1.0
//   sc - scaling applied to the random value/percentage
//   cm - change multiple to round to.  Use 0.0 for no rounding

float delta( float v, float vmin, float vmax, int dt, float cp, float cb, float sc, float cm) {

  float lo;
  float hi;
  float x;
  float h;
  float r;
  float delta_out;

  // Assume no change to the current value
  delta_out = v;

  r = rand(0.0, 1.0);

  // If random r is less than the change percentage then we do the change
  if (cp > 0.0) { if (r <= cp) {

    if (dt == DELTA_FROM_RANGE) {

      if (cb > 0.0) {

        // Positive bias
        lo = (vmin - v) - ((vmin - v) * cb);
        hi = vmax - v;

      } else {

        // Negative bias
        lo = vmin - v;
        hi = (vmax - v) + ((vmax - v) * cb);

      }

    // Else use percentages
    } else {

      if (cb > 0.0) {

        // Positive bias
        lo = -1.0 + cb;
        hi = 1.0;

      } else {

        // Negative bias
        lo = -1.0;
        hi = 1.0 + cb;

      }
    }

    if (dp_osc1_tune_delta_type == DELTA_FROM_RANGE) {

      if (cm > 0.0) {

        r = rand(lo, hi) * sc;

        x = v + r;

        if (x < 0.0) { h = -0.5; } else { h = 0.5; };

        int c = ((x / cm) + h);

        delta_out = c * cm;

      } else {

        r = rand(lo, hi) * sc;

        delta_out = v + r;
      }

    // Else do the delta from percentage of current value
    } else {

      if (cm > 0.0) {

        r = rand(lo, hi) * sc;

        x = v + (v * r);

        if (x < 0.0) { h = -0.5; } else { h = 0.5; };

        int c = ((x / cm) + h);

        delta_out = c * cm;

      } else {

        r = rand(lo, hi) * sc;

        delta_out = v + (v * r);
      }

    }

    if (delta_out < vmin) delta_out = vmin;
    if (delta_out > vmax) delta_out = vmax;

  }}

  return delta_out;
}

Oscillator[1].Tune = delta(Oscillator[1].Tune, Oscillator[1].Tune.min, Oscillator[1].Tune.max, DELTA_FROM_RANGE, 1.0, -0.5, 1.0, 12.0);

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